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ASK THE PROFESSOR FORUM

Course Documents

Chapter 1 - Intro

Chapter 2 - Methods for Describing Sets of Data

Chapter 3 - Probability

Chapter 4 - Discrete Random Variables

Chapter 5 - Normal Random Variables

Chapter 6 - Sampling Distributions

Chapter 7 - Confidence Intervals

Chapter 8 - Tests of Hypothesis: One Sample

Chapter 9 - Confidence Intervals and Hypothesis Tests: Two Samples

Sample Exam I: Chapters 1 & 2

Sample Exam II: Chapters 3 & 4

Sample Exam III: Chapters 5 & 6

Sample Exam IV: Chapters 7 & 8

Ask the Professor Forum

Hey Professor,
I need help with chapter 8 question 33. Im not getting the same p-value as the answer. Instead of .0041 I get .0039. Im not sure what Im doing wrong.
Thanks!

Posted to STATS 2 on Friday, September 20, 2013   Replies: 1


Professor Mcguckian
09/20/2013
11:34 AM EST

Hi Peggy,

It could be the way you are rounding your test statistic.  The calculation should be (11 - 10) / [2.11 / root(31)] = 2.638... which rounds to 2.64.

When we look up 2.64 on the z-table we get 0.4959.  Then we use that value to get the final answer 0.5000 - 0.4959 = 0.0041. 

Let me know if that clears up the issue, but it seems the only way you could get 0.0039 is if your test statistic was 2.66. That makes me think there is a rounding issue at play.

Professor McGuckian

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